1. Field of the Invention
The present invention relates to a method and apparatus for allocating uplink (UL) resource, and more particularly, to a method and apparatus for allocating UL resource in a network terminal of a wireless communication system, to realize non-contiguous UL resource allocation.
2. Description of the Prior Art
Long Term Evolution wireless communications system (LTE system), an advanced high-speed wireless communications system established upon the 3G mobile telecommunications system, supports only packet-switched transmission, and tends to implement both Medium Access Control (MAC) layer and Radio Link Control (RLC) layer in one single communication site, such as in Node B alone rather than in Node B (NB) and RNC (Radio Network Controller) respectively, so that the system structure becomes simple.
However, in order to meet requirements of all kinds of future services, the 3rd Generation Partnership Project (3GPP) has started to work out a next generation of the LTE system: LTE Advanced (LTE-A) system, to support wider transmission bandwidths, e.g. up to 100 MHz and for spectrum aggregation. Core technology of the LTE-A system and the LTE system is Orthogonal Frequency-Division Multiplexing (OFDM), which utilizes Orthogonal Frequency Division Multiple Access (OFDMA) for downlink (DL) transmission, and Single Carrier Frequency Division Multiple Access (SC-FDMA) for uplink transmission, so as to reduce power consumption.
In the LTE-A system, an eNB (evolved NB) can provides UL/DL transmission services to multiple mobile terminals at the same time, and thus has to effectively allocate limited transmission time and bandwidth resources to all mobile terminals, to ensure each mobile terminal can efficiently complete required transmission. A resource block (RB) is a unit for transmission resource allocation, and is allocated by a network terminal to user equipments (UEs). Each resource block comprises a plurality of resource elements, and a resource element is corresponding to an OFDMA symbol in DL transmission, while corresponding to an SC-FDMA symbol in UL transmission. Besides, a specific number of resource blocks can further compose a resource block group (RBG), which can be utilized as a unit for resource allocation as well.
Conventionally, the LTE-A system supports contiguous UL resource allocation, i.e. the network terminal allocates multiple contiguous UL resource blocks to one UE. However, the contiguous resource allocation cannot meet all kinds of requirements in the UL transmission, and thus industry evolves toward non-contiguous UL resource allocation.
In the non-contiguous UL resource allocation, the network terminal allocates more than one resource block cluster to a UE for UL transmission. Under such a condition, factors, such as a length, a number, a starting location and an ending location of a cluster, cause resource allocation becoming various and complex. Therefore, how to effectively allocate non-contiguous UL resources has become an issue in the industry.